Page 255 - Lego Mindstorms

Robot 9 • The SpinnerBot

As a designer, you’ll always be striving to squeeze a few more features into
your robot without using any more RCX outputs. Using only two motors, the
SpinnerBot allows you to experiment with driving, grabbing, lifting, and
replacing objects. This robot gets its name from the fact that it spends a lot of
time spinning: In order to navigate, it either moves forward or turns to the left.
Nevertheless, the SpinnerBot can get wherever it needs to go using these two
abilities, and when it gets there, it can grab and lift objects using the gripper
arm powered by the second motor. The SpinnerBot uses touch sensors to detect
the flags it collects, and it uses a light sensor in order to stay within the bounds
of the dark oval on the Test Pad (the Test Pad is the large printed sheet that
came with your RIS 2.0 kit).
Using the language NQC (Not Quite C), I have written a Capture-the-Flag
program for the robot, which hunts around the confines of the Test Pad for a
specially designed flag. When the robot encounters a flag, it captures it using
the grabbers, and lifts it off the ground using the lift arm. As a further chal-
lenge, you might try setting up your own arena with a dark border and a
medium-shaded “home” area. You could then program SpinnerBot to search
for flags outside its home, retrieve them, and deposit them in its nest. You can
find the Capture-the-Flag program on the Syngress Solutions Web site
(www.syngress.com/solutions).

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